| abstract |
A probe for use within a catheter is disclosed. The probe transducer portion is constructed of a crystal hollow cylinder with an inside lead attached to the inner surface of the crystal cylinder. One end of the outside lead is positioned close to the outer surface, in a plane tangential to the outer surface, and is coupled to the outer surface of the crystal cylinder by a thin sputtered layer of conductive material. The probe transducer also includes a layer of acoustically absorbing material on the proximal end of the crystal, and layer of acoustically coupling material on the distal end of the crystal cylinder. The transducer element simultaneously generates an axially oriented signal beam at one frequency and a radially oriented signal beam at 2 different frequency. The signal beams are analyzed to calculate the blood flow area and the blood flow velocity, the product of which is the blood flow rate. |